1. Field of the Invention
Standing valves are frequently installed in the lower end of well flow conductors to act as one way check valves. A typical standing valve allows formation fluids within a well bore to flow into the well flow conductor and through the well flow conductor to the well surface. The standing valve prevents fluids injected into the well flow conductor at the well surface from flowing out the lower end thereof and into the formation surrounding the well bore.
2. Description of the Prior Art
Otis Engineering Corporation Pumpdown Completion Equipment & Service Catalog (OEC 5113A) shows on page 12 examples of standing valves used in pumpdown well completions. A typical standing valve is shown on page 24 of this stame catalog.
U.S. Pat. No. 3,603,394 invented by George Max Raulins shows a combination standing valve and velocity operated safety valve. U.S. Pat. No. 3,603,394 is incorporated by reference for all purposes in this patent application.